[Functions] Add +-*/ operators and reshape for FDTensor (#655)

* Add +-*/ functions

* Add same dims test case for operations

* add broadcast 0

* Add broadcast dim2 testcase

* Add broadcast dim3 and dim4 testcase

* Add +-*/ operators

* Add mixed operation

* refresh code style

* Add reshape op

* update code style

fastdeploy/function/elementwise.h

@@ -0,0 +1,60 @@
+// Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include "fastdeploy/core/fd_tensor.h"
+
+namespace fastdeploy {
+namespace function {
+
+/** Excute the add operation for input FDTensors. *out = x + y.
+    @param x The input tensor.
+    @param y The input tensor.
+    @param out The output tensor which stores the result.
+*/
+FASTDEPLOY_DECL void Add(const FDTensor& x, const FDTensor& y, FDTensor* out);
+
+FASTDEPLOY_DECL FDTensor operator+(const FDTensor& x, const FDTensor& y);
+
+/** Excute the subtract operation for input FDTensors.  *out = x - y.
+    @param x The input tensor.
+    @param y The input tensor.
+    @param out The output tensor which stores the result.
+*/
+FASTDEPLOY_DECL void Subtract(const FDTensor& x, const FDTensor& y,
+                              FDTensor* out);
+
+FASTDEPLOY_DECL FDTensor operator-(const FDTensor& x, const FDTensor& y);
+
+/** Excute the multiply operation for input FDTensors.  *out = x * y.
+    @param x The input tensor.
+    @param y The input tensor.
+    @param out The output tensor which stores the result.
+*/
+FASTDEPLOY_DECL void Multiply(const FDTensor& x, const FDTensor& y,
+                              FDTensor* out);
+
+FASTDEPLOY_DECL FDTensor operator*(const FDTensor& x, const FDTensor& y);
+/** Excute the divide operation for input FDTensors.  *out = x / y.
+    @param x The input tensor.
+    @param y The input tensor.
+    @param out The output tensor which stores the result.
+*/
+FASTDEPLOY_DECL void Divide(const FDTensor& x, const FDTensor& y,
+                            FDTensor* out);
+FASTDEPLOY_DECL FDTensor operator/(const FDTensor& x, const FDTensor& y);
+
+}  // namespace function
+}  // namespace fastdeploy